Safety device



of its original purpose-if possible.

Patented June 22, 1943 UNITED STATE-S PATENT OFFICE Company, Incorporated, New York, N. Y., a corporation of New York Application July 31,1942, SerialNo. 453,130 6 Claims. (Cl. 192-429) This invention relates to a safety device, and more particularly to a device for ensuring safety while adjusting a temporarily halted power driven tool.

. There are various power driven apparatus employed in modern manufacturing in which power means are provided to a rotary tool such as a drill, bit, wrench, socket, screw driver blade, or the like, through some form of slippable clutch means by which power can be applied to the tool'only up to a certain predetermined maximum value, usually fixed by frictional engagement of the clutch'members under some form of spring tension. The clutch parts, i. e., the frictionally engaging members and the spring means, are then usually so constructed that the spring pressure, under which the frictional members engage each other, may be adjustably varied to adjust the maximum power deliverable through the clutch means, according to the requirements of the particular job in hand. Such power driven apparatus is often, of recent years, made to be light and portable within the limits imposed by the electrical cable, steam. hose or air hose which supplies power for its operation. the gun type of hand drill or screw driver, having roughly the appearance of an oversized pistol with the rotating clutch and tool as barrel, with a pistol grip for convenience of manipulation, and with a trigger controlling the power switch or valve, is becoming 'a familiar feature in the manufacturing picture of late. When such a gun tool is employed with its rotary clutch and tool axis horizontal, it is conveniently and easily manipulated accurately by being held in the manner for which its structure is designed, i. e.,- with one'hand grasping the pistol grip and operating the switch conveniently then under one finger, while the other hand grasps the body casing to help guide the tool. But when the drill or screw driver is to operate vertically and at or above the operators chest level, the apparatus cannot conveniently be held thus; and, in particular, it is difficult to grip it in such fashion that both the power control trigger and the tool are accurately controllable at the same time. Suchtools are therefore generally designed and made in two distinct forms, the gun type for use in a horizontal position, and a generally cylindrical form without any pistol grip and with the power trigger located for convenience when the :tool is used vertically. However, under the abnormal conditions of the day, it is eminently desirable to adapt each such .tooldfcr uses outside Hence the In particular,

gun type of these tools is frequently provided with auxiliary added means to enable the power trigger to be actuated by means of a lever convenient for manipulation when the tool is being operated vertically, Usually, the adjustment of the clutch is accomplished by effecting relative rotation of one or the other of a pair of members of the clutch units to increase or lessen the tension of the spring which urges the friction drive members of the clutch together. 'Wlth the ordinary gun type of tool, in its unmodified form, this operation affords neither difficulty nor danger, since the clutch, where the adjustment is to be made, and the power trigger are at opposite endsof the apparatus. But when a gun type tool is modified, as described, to render it easily manipula-ble in a vertical position, the auxiliary power lever is most conveniently located roughly beside and parallel to the clutch. There is then a possibility that while the clutch tension is being adjusted, the power lever may be accidentally tripped and the clutch set in motion.

An object of the present invention is to provide simple, efficient and reliable means to aid in the adjustment of power drivable members while simultaneously preventing actuation of a neighboring power control member.

With the above and other objects in view, the invention may be embodied in a device removably mountable upon a rotatable and adjustable clutch mechanism and provided with means to engage and hold against rotation a member of the clutch and with means to engage and prevent actuation of a neighboring power control member.

Other objects and features will appear from the following detailed description of embodiments of the invention taken in connection with the accompanying drawing in which the same reference numerals are applied to identical fig- .uresin the drawing and in which Fig. lis a view in side elevation of a gun type power screw driver modified for vertical operation and provided with a device embodying the invention;

Fig. 2 is an enlarged section on the line 2-2 of Fig. 1,. with parts broken away; Fig. 3 is a broken side view of the clutch and device enlarged;

Fig. 4 'is a partial view corresponding to Fig. 1 showing a modified vform of the invention; and

Fig. 5 is an enlarged section on the line 5-5 of Fig. 4.

The invention resides wholly in the device to be applied to the tool to simultaneously facilitate adjustment and preventpower actuation of the driving of the rotatably drivable members, and provided with a yoke to engage one of the relatively rotatably adjustable members to prevent the same from rotation while the other member is being rotatably adjusted relatively thereto.

3. A device for use in adjusting one of a pair of rotatably drivable and relatively rotatably adjustable members forming part of an assembly and having an associated driving control lever disposed relatively close thereto, the said device comprising a body member to be mounted on the assemblygenerally and provided with means to engage the control lever and thereby prevent driving of the rotatably drivable members, and provided with a yoke and a pin slidable therein to engage one of the relatively rotatably adjustable members to prevent the same from rotation while the other member is being rotatably adjusted relatively thereto.

4. The combination with an apparatus having a pair of rotatably drivable and relatively rotatably adjustable'members forming part of an assembly and having an associated driving control member disposed relatively close thereto, of a device comprising a body member to be mounted on the assembly generally and provided with means to engage the control member and thereby prevent driving of the rotatably drivable members, and provided with means to engage one of the relatively rotatably adjustable members to prevent the same from rotation While the other member is being rotatably adjusted relatively thereto.

5. The combination with an apparatus having a pair of rotatably drivable and relatively rotatably adjustable members forming part of an assembly and having an associated driving control lever disposed relatively close thereto, of a device comprising a body member to be mounted on the assembly generally and provided with means to engage the control lever and thereby prevent driving of the rotatably drivable members, and provided with a yoke to engage one of the relatively rotatably adjustable members to prevent the same from rotation while the other member is being rotatably adjusted relatively thereto.

6. The combination with an apparatus having a pair of rotatably drivable and relatively rotatably adjustable members forming part of an assembly and having an associated driving control lever disposed relatively close thereto, of a device comprising a body member to be mounted on the assembly generally and provided with means to engage the control lever and thereby prevent driving of the rotatably drivable members, and provided with a yoke and a pin slidable therein to engage one of the relatively rotatably adjustable members to prevent the same from rotation while the other member is being rotatably adjusted relatively thereto.

ERNEST A. FISCHER. EARL C. MOSS. 

